Pattern formation material and pattern formation method

ABSTRACT

A resist film is formed by applying, on a substrate, a pattern formation material containing a polymer including a first unit represented by Chemical Formula 1 and a second unit represented by Chemical Formula 2, and an acid generator:  
                 
 
                 
 
     wherein R 1  and R 3  are the same or different and selected from the group consisting of an alkyl group, a chlorine atom and an alkyl group including a fluorine atom; R 2  is a protecting group released by an acid; and m is an integer of 0 through 5. Subsequently, the resist film is irradiated with exposing light of a wavelength shorter than a 180 nm band for pattern exposure, and a resist pattern is formed by developing the resist film after the pattern exposure.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a pattern formation method and apattern formation material, and more particularly, it relates to apattern formation method for forming a resist pattern, used for forminga semiconductor device or a semiconductor integrated circuit on asemiconductor substrate, by using exposing light of a wavelength shorterthan a 180 nm band and a pattern formation material used in the patternformation method.

[0002] Currently, in fabrication of a mass storage semiconductorintegrated circuit, such as a 64 Mbit dynamic random access memory(DRAM) and a logic device or a system LSI with a 0.25 μm through 0.15 μmrule, a resist pattern is formed by using a chemically amplified resistmaterial including a polyhydroxystyrene derivative and an acid generatoras principal constituents with KrF excimer laser (of a wavelength of a248 nm band) used as exposing light.

[0003] Moreover, for fabrication of a 256 Mbit DRAM, a 1 Gbit DRAM or asystem LSI with a 0.15 μm through 0.13 μm rule, a pattern formationmethod using, as exposing light, ArF excimer laser lasing at a shorterwavelength (of a 193 nm band) than the KrF excimer laser is now underdevelopment.

[0004] The resist material including a polyhydroxystyrene derivative asa principal constituent has high absorbance against light of awavelength of a 193 nm band because of an aromatic ring includedtherein. Therefore, exposing light of a wavelength of a 193 nm bandcannot uniformly reach the bottom of a resist film, and hence, a patterncannot be formed in a good shape. Accordingly, the resist materialincluding a polyhydroxystyrene derivative as a principal constituentcannot be used when the ArF excimer laser is used as the exposing light.

[0005] Therefore, a chemically amplified resist material including, as aprincipal constituent, a polyacrylic acid derivative or apolycycloolefin derivative having no aromatic ring is used when the ArFexcimer laser is used as the exposing light.

[0006] On the other hand, as exposing light for a pattern formationmethod capable of coping with high resolution, an electron beam (EB) andthe like are being examined.

[0007] When the EB is used as the exposing light, however, thethroughput is disadvantageously low, and hence, the EB is not suitableto mass production.

[0008] Accordingly, in order to form a resist pattern finer than 0.10μm, it is necessary to use exposing light of a wavelength shorter thanthat of the ArF excimer laser, such as Xe₂ laser (of a wavelength of a172 nm band), F₂ laser (of a wavelength of a 157 nm band), Kr₂ laser (ofa wavelength of a 146 nm band), ArKr laser (of a wavelength of 134 nmband), Ar₂ laser (of a wavelength of a 126 nm band), soft-X rays (of awavelength of a 13, 11 or 5 nm band) and hard-X rays (of a wavelengthshorter than a 1 nm band). In other words, a resist pattern is requiredto be formed by using exposing light of a wavelength shorter than a 180nm band.

[0009] Therefore, the present inventors have formed resist patterns byconducting pattern exposure using F₂ laser (of a wavelength of a 157 nmband) on resist films formed from conventionally known chemicallyamplified resist materials respectively including a polyhydroxystyrenederivative represented by Chemical Formula A, a polyacrylic acidderivative represented by Chemical Formula B and a polycycloolefinderivative represented by Chemical Formula C.

[0010] Now, a method for forming a resist pattern by using any of theaforementioned conventional chemically amplified resist materials andproblems arising in the conventional method will be described withreference to FIGS. 2A through 2D.

[0011] First, as shown in FIG. 2A, the chemically amplified resistmaterial is applied on a semiconductor substrate 1 by spin coating andthe resultant is heated, so as to form a resist film 2 with a thicknessof 0.3 μm. Thereafter, as shown in FIG. 2B, the resist film 2 isirradiated with a F₂ laser beam 4 through a mask 3 for pattern exposure.Thus, an acid is generated from the acid generator in an exposed portion2 a of the resist film 2 while no acid is generated in an unexposedportion 2 b of the resist film 2.

[0012] Next, as shown in FIG. 2C, the semiconductor substrate 1 isheated with a hot plate at, for example, 100° C. for 60 seconds.

[0013] Then, the resist film 2 is developed with an alkaline developer,thereby forming a resist pattern 5.

[0014] However, as shown in FIG. 2D, the resist pattern 5 cannot beformed in a good pattern shape, and there remains much scum on thesemiconductor substrate 1. Such problems occur not only in using the F₂laser beam as the exposing light but also in using any of the otherlight of a wavelength shorter than a 180 nm band.

[0015] Accordingly, a resist pattern cannot be practically formed byirradiating a resist film made from any of the aforementioned chemicallyamplified resist materials with light of a wavelength shorter than a 180nm band.

SUMMARY OF THE INVENTION

[0016] In consideration of the aforementioned conventional problems, anobject of the invention is forming a resist pattern in a good patternshape by using exposing light of a wavelength shorter than a 180 nm bandwith minimally producing scum.

[0017] The present inventors have studied the causes of the conventionalproblems occurring in using the conventional chemically amplified resistmaterials and have found the following:

[0018] First, the chemically amplified resist materials have highabsorbance against light of a wavelength shorter than a 180 nm band. Forexample, a resist film with a thickness of 100 nm made from thechemically amplified resist material including a polyhydroxystyrenederivative as a principal constituent has transmittance of 20% at mostagainst a F₂ laser beam (of a wavelength of a 157 nm band).

[0019] Therefore, various examination has been made on means forimproving the transmittance of a chemically amplified resist materialagainst light of a wavelength shorter than a 180 nm band. As a result,it has been found that the transmittance of a chemically amplifiedresist material against light of a wavelength shorter than a 180 nm bandcan be improved when a unit of a polyhydroxystyrene derivative havinghexafluoroisopropyl alcohol ((CF₃)₂C—OH) on its side chain is introducedinto a base polymer.

[0020] Furthermore, when any of the aforementioned chemically amplifiedresist materials, particularly the resist material including apolyhydroxystyrene derivative, is irradiated with light of a wavelengthshorter than a 180 nm band, a reaction is caused regardless of thefunction of an acid, so that a hydrogen atom bonded to carbon located atthe á-position of the principal chain of the polymer can be released andthat polymer radicals from which the hydrogen atoms are released canbond to each other to be crosslinked. As a result, the solubility of anexposed portion of the resist film in a developer is degraded.Therefore, means for preventing the crosslinking reaction of theprincipal chains of the polymer of a chemically amplified resistmaterial has been variously studied. As a result, it has been found thatthe crosslinking reaction of the principal chains can be avoided bysubstituting an alkyl group or a chlorine atom for a hydrogen atomlocated at the a-position of the principal chain of the polymer.

[0021] Moreover, since the polymer has an aromatic ring on a side chainthereof, the dry etching resistance and the heat resistance of theresist film can be improved.

[0022] In addition, when hexafluoroisopropanol is introduced into anaromatic ring of the polyhydroxystyrene derivative, the transmittanceagainst light of a wavelength shorter than a 180 nm band can beimproved, and the solubility in a developer of a hydroxyl group fromwhich a protecting group has been released can be improved. As a result,the contrast in the solubility between an exposed portion and anunexposed portion of the resist film can be improved.

[0023] The present invention was devised on the basis of theaforementioned findings, and specifically provides pattern formationmaterials and methods described below.

[0024] The first pattern formation material of this invention comprisesa polymer including a first unit represented by Chemical Formula 1 and asecond unit represented by Chemical Formula 2; and an acid generator:

[0025] wherein R₁ and R₃ are the same or different and selected from thegroup consisting of an alkyl group, a chlorine atom and an alkyl groupincluding a fluorine atom; R₂ is a protecting group released by an acid;and m is an integer of 0 through 5.

[0026] In the first pattern formation material, since the first unit hasa hexafluoroisopropyl group and the second unit has a cyano group, thetransmittance against light of a wavelength shorter than a 180 nm bandcan be largely improved. Furthermore, since an alkyl group, a chlorineatom or an alkyl group including a fluorine atom is substituted forhydrogen atoms located at the a-positions of the principal chains of thefirst and second units, the crosslinking reaction of the principalchains can be prevented, resulting in improving the solubility of anexposed portion of a resist film in a developer. Moreover, since analcohol portion of the first unit has a trifluoromethyl group, thesolubility of a hydroxyl group in the developer can be improved, so asto improve the solubility of the exposed portion of the resist film inthe developer. Accordingly, the contrast in the solubility between theexposed portion and an unexposed portion of the resist film can belargely improved. In addition, since the first unit has a benzene ring,the dry etching resistance can be improved.

[0027] The second pattern formation material of this invention comprisesa polymer including a first unit represented by Chemical Formula 3 and asecond unit represented by Chemical Formula 4; and an acid generator:

[0028] wherein R₁ and R₄ are the same or different and selected from thegroup consisting of an alkyl group, a chlorine atom and an alkyl groupincluding a fluorine atom; R₂ is a protecting group released by an acid;and m is an integer of 0 through 5.

[0029] In the second pattern formation material, since the first unithas a hexafluoroisopropyl group and the second unit has a cyano group,the transmittance against light of a wavelength shorter than a 180 nmband can be largely improved. Furthermore, since an alkyl group, achlorine atom or an alkyl group including a fluorine atom is substitutedfor hydrogen atoms located at the a-positions of the principal chains ofthe first and second units, the crosslinking reaction of the principalchains can be prevented, resulting in improving the solubility of anexposed portion of a resist film in a developer. Moreover, since analcohol portion of the first unit has a trifluoromethyl group, thesolubility of a hydroxyl group in the developer can be improved, so asto improve the solubility of the exposed portion of the resist film inthe developer. Accordingly, the contrast in the solubility between theexposed portion and an unexposed portion of the resist film can belargely improved. In addition, since the first and second units have abenzene ring, the dry etching resistance can be improved.

[0030] The third pattern formation material of this invention comprisesa polymer including a first unit represented by Chemical Formula 5, asecond unit represented by Chemical Formula 6 and a third unitrepresented by Chemical Formula 7; and an acid generator:

[0031] wherein R₁, R₃ and R₅ are the same or different and selected fromthe group consisting of an alkyl group, a chlorine atom and an alkylgroup including a fluorine atom; R₂ is a protecting group released by anacid; and m is an integer of 0 through 5.

[0032] In the third pattern formation material, since the first unit hasa hexafluoroisopropyl group, the transmittance against light of awavelength shorter than a 180 nm band can be largely improved.Furthermore, since an alkyl group, a chlorine atom or an alkyl groupincluding a fluorine atom is substituted for hydrogen atoms located atthe a-positions of the principal chains of the first, second and thirdunits, the crosslinking reaction of the principal chains can beprevented, resulting in improving the solubility of an exposed portionof a resist film in a developer. Moreover, since an alcohol portion ofthe first unit has a trifluoromethyl group, the solubility of a hydroxylgroup in the developer can be improved, so as to improve the solubilityof the exposed portion of the resist film in the developer. Accordingly,the contrast in the solubility between the exposed portion and anunexposed portion of the resist film can be largely improved. Inaddition, since the first and third units have a benzene ring, the dryetching resistance can be largely improved. Moreover, since the thirdunit has a hydroxyl group, the wettability is improved so as to improvethe adhesion to the substrate, and the dissolving rate in an alkalinedeveloper can be controlled by adjusting the ratio of the third unit inthe polymer.

[0033] The fourth pattern formation material of this invention comprisesa polymer including a first unit represented by Chemical Formula 8, asecond unit represented by Chemical Formula 9 and a third unitrepresented by Chemical Formula 10; and an acid generator:

[0034] wherein R₁, R₄ and R₅ are the same or different and selected fromthe group consisting of an alkyl group, a chlorine atom and an alkylgroup including a fluorine atom; R₂ is a protecting group released by anacid; and m is an integer of 0 through 5.

[0035] In the fourth pattern formation material, since the first unithas a hexafluoroisopropyl group, the transmittance against light of awavelength shorter than a 180 nm band can be largely improved.Furthermore, since an alkyl group, a chlorine atom or an alkyl groupincluding a fluorine atom is substituted for hydrogen atoms located atthe a-positions of the principal chains of the first, second and thirdunits, the crosslinking reaction of the principal chains can beprevented, resulting in improving the solubility of an exposed portionof a resist film in a developer. Moreover, since an alcohol portion ofthe first unit has a trifluoromethyl group, the solubility of a hydroxylgroup in the developer can be improved, so as to improve the solubilityof the exposed portion of the resist film in the developer. Accordingly,the contrast in the solubility between the exposed portion and anunexposed portion of the resist film can be largely improved. Inaddition, since the first, second and third units have a benzene ring,the dry etching resistance can be largely improved. Furthermore, sincethe third unit has a hydroxyl group, the wettability is improved so asto improve the adhesion to the substrate, and the dissolving rate in analkaline developer can be controlled by adjusting the ratio of the thirdunit in the polymer.

[0036] Specific examples of the protecting group released by an acidrepresented by R₂ in the aforementioned general formulas are thoserepresented by Chemical Formula 11:

[0037] The first pattern formation method of this invention comprisesthe steps of forming a resist film by applying, on a substrate, thefirst pattern formation material; irradiating the resist film withexposing light of a wavelength shorter than a 180 nm band for patternexposure; and forming a resist pattern by developing the resist filmafter the pattern exposure.

[0038] In the first pattern formation method, since the first patternformation material is used, the transmittance against light of awavelength shorter than a 180 nm band can be largely improved, thesolubility of an exposed portion of the resist film in a developer canbe improved, the dry etching resistance can be improved, and thecontrast in the solubility between the exposed portion and an unexposedportion of the resist film can be largely improved.

[0039] The second pattern formation method of this invention comprisesthe steps of forming a resist film by applying, on a substrate, thesecond pattern formation material; irradiating the resist film withexposing light of a wavelength shorter than a 180 nm band for patternexposure; and forming a resist pattern by developing the resist filmafter the pattern exposure.

[0040] In the second pattern formation method, since the second patternformation material is used, the transmittance against light of awavelength shorter than a 180 nm band can be largely improved, thesolubility of an exposed portion of the resist film in a developer canbe improved, the dry etching resistance can be improved, and thecontrast in the solubility between the exposed portion and an unexposedportion of the resist film can be largely improved.

[0041] The third pattern formation method of this invention comprisesthe steps of forming a resist film by applying, on a substrate, thethird pattern formation material; irradiating the resist film withexposing light of a wavelength shorter than a 180 nm band for patternexposure; and forming a resist pattern by developing the resist filmafter the pattern exposure.

[0042] In the third pattern formation method, since the third patternformation material is used, the transmittance against light of awavelength shorter than a 180 nm band can be largely improved, thesolubility of an exposed portion of the resist film in a developer canbe improved, the dry etching resistance can be improved, and thecontrast in the solubility between the exposed portion and an unexposedportion of the resist film can be largely improved. Furthermore, thewettability of the pattern formation material can be improved so as toimprove the adhesion to the substrate, and the dissolving rate in analkaline developer can be controlled by adjusting the ratio of the thirdunit in the polymer.

[0043] The fourth pattern formation method of this invention comprisesthe steps of forming a resist film by applying, on a substrate, thefourth pattern formation material; irradiating the resist film withexposing light of a wavelength shorter than a 180 nm band for patternexposure; and forming a resist pattern by developing the resist filmafter the pattern exposure.

[0044] In the fourth pattern formation method, since the fourth patternformation material is used, the transmittance against light of awavelength shorter than a 180 nm band can be largely improved, thesolubility of an exposed portion of the resist film in a developer canbe improved, the dry etching resistance can be improved, and thecontrast in the solubility between the exposed portion and an unexposedportion of the resist film can be largely improved. Furthermore, thewettability of the pattern formation material can be improved so as toimprove the adhesion to the substrate, and the dissolving rate in analkaline developer can be controlled by adjusting the ratio of the thirdunit in the polymer.

[0045] In any of the first through fourth pattern formation methods, theexposing light can be light of a wavelength of a 110 through 180 nm bandsuch as a Xe₂laser beam, a F₂ laser beam, a Kr₂ laser beam, an ArKrlaser beam or an Ar₂ laser beam; soft-X rays of a wavelength of a 1through 30 nm band; or hard-X rays of a wavelength shorter than a 1 nmband.

BRIEF DESCRIPTION OF THE DRAWINGS

[0046]FIGS. 1A, 1B, 1C and ID are cross-sectional views for showingprocedures in a pattern formation method according to any of Embodiments1 through 4 of the invention; and

[0047]FIGS. 2A, 2B, 2C and 2D are cross-sectional views for showingprocedures in a conventional pattern formation method.

DETAILED DESCRIPTION OF THE INVENTION

[0048] Embodiment 1

[0049] A pattern formation material and a pattern formation methodaccording to Embodiment 1 of the invention will now be described withreference to FIGS. 1A through 1D.

[0050] In this embodiment, the first pattern formation material and thefirst pattern formation method described above are embodied, and thespecific composition of a resist material of this embodiment is asfollows:

[0051] Base polymer: a polymer represented by Chemical Formula 12 below

[0052] Acid generator: triphenylsulfonium triflate (2 wt % based on thebase polymer)

[0053] Solvent: diglime

[0054] First, as shown in FIG. 1A, the resist material having theabove-described composition is applied on a semiconductor substrate 10by spin coating, thereby forming a resist film 11 with a thickness of0.2 μm. At this point, since the base polymer is alkali-refractory, theresist film 11 is alkali-refractory.

[0055] Next, as shown in FIG. 1B, the resist film 11 is subjected topattern exposure by irradiating through a mask 12 with F₂ excimer laser13 (of a wavelength of a 157 nm band). Thus, an acid is generated fromthe acid generator in an exposed portion 11 a of the resist film 11while no acid is generated in an unexposed portion 11 b of the resistfilm 11.

[0056] Then, as shown in FIG. 1C, the semiconductor substrate 10together with the resist film 11 is heated with a hot plate 14. Thus,the base polymer is heated in the presence of the acid in the exposedportion 11 a of the resist film 11, so as to release a protecting groupof a unit on the left hand side in Chemical Formula 12. As a result, thebase polymer becomes alkali-soluble.

[0057] Subsequently, the resist film 11 is developed with an alkalinedeveloper such as a tetramethylammonium hydroxide aqueous solution.Thus, the exposed portion 11 a of the resist film 11 is dissolved in thedeveloper, so that a resist pattern 15 can be formed from the unexposedportion 11 b of the resist film 11 as shown in FIG. 1D.

[0058] In the base polymer of Embodiment 1 represented by ChemicalFormula 12, R₁ and R₃ of first and second units respectively representedby Chemical Formulas 1 and 2 are both CH₃. Instead, R₁ and R₂ may beanother alkyl group such as C₂H₅, a chlorine atom or an alkyl groupincluding a fluorine atom such as CF₃. In this case, R₁ and R₃ may bethe same or different from each other.

[0059] Also, in the base polymer of Embodiment 1 represented by ChemicalFormula 12, m of the first unit represented by Chemical Formula 1 is 1.Instead, m may be 0, 2, 3, 4 or 5.

[0060] Embodiment 2

[0061] A pattern formation material and a pattern formation methodaccording to Embodiment 2 of the invention will now be described.Embodiment 2 is different from Embodiment 1 in the resist materialalone, and hence, the resist material alone will be herein described.

[0062] In this embodiment, the second pattern formation material and thesecond pattern formation method described above are embodied, and thespecific composition of the resist material is as follows:

[0063] Base polymer: a polymer represented by Chemical Formula 13 below

[0064] Acid generator: triphenylsulfonium triflate (2 wt % based on thebase polymer)

[0065] Solvent: diglime

[0066] In the base polymer of Embodiment 2 represented by ChemicalFormula 13, R₁ and R₄ of first and second units respectively representedby Chemical Formulas 3 and 4 are both CF₃. Instead, they may be an alkylgroup such as CH₃ or C₂H₅, a chlorine atom or another alkyl groupincluding a fluorine atom. In this case, R₁ and R₄ may be the same ordifferent from each other.

[0067] Also, in the base polymer of Embodiment 2 represented by ChemicalFormula 13, m of the first unit represented by Chemical Formula 3 is 0.Instead, m may be 1, 2, 3, 4 or 5.

[0068] Embodiment 3

[0069] A pattern formation material and a pattern formation methodaccording to Embodiment 3 of the invention will now be described.Embodiment 3 is different from Embodiment 1 in the resist materialalone, and hence, the resist material alone will be herein described.

[0070] In this embodiment, the third pattern formation material and thethird pattern formation method described above are embodied, and thespecific composition of the resist material is as follows:

[0071] Base polymer: a polymer represented by Chemical Formula 14 below

[0072] Acid generator: triphenylsulfonium triflate (2 wt % based on thebase polymer)

[0073] Solvent: diglime

[0074] In the base polymer of Embodiment 3 represented by ChemicalFormula 14, R₁, R₃ and R₅ of first, second and third units respectivelyrepresented by Chemical Formulas 5, 6 and 7 are all CH₃. Instead, theymay be another alkyl group such as C₂H₅, a chlorine atom or an alkylgroup including a fluorine atom such as CF₃. In this case, R₁, R₃ and R₅may be the same or different from one another.

[0075] Also, in the base polymer of Embodiment 3 represented by ChemicalFormula 14, m of the first unit represented by Chemical Formula 5 is 1.Instead, m may be 0, 2, 3, 4 or 5.

Embodiment 4

[0076] A pattern formation material and a pattern formation methodaccording to Embodiment 4 of the invention will now be described.Embodiment 4 is different from Embodiment 1 in the resist materialalone, and hence, the resist material alone will be herein described.

[0077] In this embodiment, the fourth pattern formation material and thefourth pattern formation method described above are embodied, and thespecific composition of the resist material is as follows:

[0078] Base polymer: a polymer represented by Chemical Formula 15 below

[0079] Acid generator: triphenylsulfonium triflate (2 wt % based on thebase polymer)

[0080] Solvent: diglime

[0081] In the base polymer of Embodiment 4 represented by ChemicalFormula 15, R₁, R₄ and R₅ of first, second and third units respectivelyrepresented by Chemical Formulas 8, 9 and 10 are all CH₃. Instead, theymay be another alkyl group such as C₂H₅, a chlorine atom or an alkylgroup including a fluorine atom such as CF₃. In this case, R₁, R₄ and R₅may be the same or different from one another.

[0082] Also, in the base polymer of Embodiment 4 represented by ChemicalFormula 15, m of the first unit represented by Chemical Formula 8 is 2.Instead, m may be 0, 1, 3, 4 or 5.

What is claimed is:
 1. A pattern formation material comprising: apolymer including a first unit represented by Chemical Formula 1 and asecond unit represented by Chemical Formula 2; and an acid generator:

wherein R₁ and R₃ are the same or different and selected from the groupconsisting of an alkyl group, a chlorine atom and an alkyl groupincluding a fluorine atom; R₂ is a protecting group released by an acid;and m is an integer of 0 through
 5. 2. A pattern formation materialcomprising: a polymer including a first unit represented by ChemicalFormula 3 and a second unit represented by Chemical Formula 4; and anacid generator:

wherein R₁ and R₄ are the same or different and selected from the groupconsisting of an alkyl group, a chlorine atom and an alkyl groupincluding a fluorine atom; R₂ is a protecting group released by an acid;and m is an integer of 0 through
 5. 3. A pattern formation materialcomprising: a polymer including a first unit represented by ChemicalFormula 5, a second unit represented by Chemical Formula 6 and a thirdunit represented by Chemical Formula 7; and an acid generator:

wherein R₁, R₃ and R₅ are the same or different and selected from thegroup consisting of an alkyl group, a chlorine atom and an alkyl groupincluding a fluorine atom; R₂ is a protecting group released by an acid;and m is an integer of 0 through
 5. 4. A pattern formation materialcomprising: a polymer including a first unit represented by ChemicalFormula 8, a second unit represented by Chemical Formula 9 and a thirdunit represented by Chemical Formula 10; and an acid generator:

wherein R₁, R₄ and R₅ are the same or different and selected from thegroup consisting of an alkyl group, a chlorine atom and an alkyl groupincluding a fluorine atom; R₂ is a protecting group released by an acid;and m is an integer of 0 through
 5. 5. A pattern formation methodcomprising the steps of: forming a resist film by applying, on asubstrate, a pattern formation material containing a polymer including afirst unit represented by Chemical Formula 1 and a second unitrepresented by Chemical Formula 2, and an acid generator:

wherein R₁ and R₃ are the same or different and selected from the groupconsisting of an alkyl group, a chlorine atom and an alkyl groupincluding a fluorine atom; R₂ is a protecting group released by an acid;and m is an integer of 0 through 5; irradiating said resist film withexposing light of a wavelength shorter than a 180 nm band for patternexposure; and forming a resist pattern by developing said resist filmafter the pattern exposure.
 6. The pattern formation method of claim 5,wherein said exposing light is a Xe₂ laser beam, a F₂ laser beam, a Kr₂laser beam, an ArKr laser beam or an Ar₂ laser beam.
 7. The patternformation method of claim 5, wherein said exposing light is soft-X rays.8. The pattern formation method of claim 5, wherein said exposing lightis hard-X rays.
 9. A pattern formation method comprising the steps of:forming a resist film by applying, on a substrate, a pattern formationmaterial containing a polymer including a first unit represented byChemical Formula 3 and a second unit represented by Chemical Formula 4,and an acid generator:

wherein R₁ and R₄ are the same or different and selected from the groupconsisting of an alkyl group, a chlorine atom and an alkyl groupincluding a fluorine atom; R₂ is a protecting group released by an acid;and m is an integer of 0 through 5; irradiating said resist film withexposing light of a wavelength shorter than a 180 nm band for patternexposure; and forming a resist pattern by developing said resist filmafter the pattern exposure.
 10. The pattern formation method of claim 9,wherein said exposing light is a Xe₂ laser beam, a F₂ laser beam, a Kr₂laser beam, an ArKr laser beam or an Ar₂ laser beam.
 11. The patternformation method of claim 9, wherein said exposing light is soft-X rays.12. The pattern formation method of claim 9, wherein said exposing lightis hard-X rays.
 13. A pattern formation method comprising the steps of:forming a resist film by applying, on a substrate, a pattern formationmaterial containing a polymer including a first unit represented byChemical Formula 5, a second unit represented by Chemical Formula 6 anda third unit represented by Chemical Formula 7, and an acid generator:

wherein R₁, R₃ and R₅ are the same or different and selected from thegroup consisting of an alkyl group, a chlorine atom and an alkyl groupincluding a fluorine atom; R₂ is a protecting group released by an acid;and m is an integer of 0 through 5; irradiating said resist film withexposing light of a wavelength shorter than a 180 nm band for patternexposure; and forming a resist pattern by developing said resist filmafter the pattern exposure.
 14. The pattern formation method of claim13, wherein said exposing light is a Xe₂ laser beam, a F₂ laser beam, aKr₂ laser beam, an ArKr laser beam or an Ar₂ laser beam.
 15. The patternformation method of claim 13, wherein said exposing light is soft-Xrays.
 16. The pattern formation method of claim 13, wherein saidexposing light is hard-X rays.
 17. A pattern formation method comprisingthe steps of: forming a resist film by applying, on a substrate, apattern formation material containing a polymer including a first unitrepresented by Chemical Formula 8, a second unit represented by ChemicalFormula 9 and a third unit represented by Chemical Formula 10, and anacid generator:

wherein R₁, R₄ and R₅ are the same or different and selected from thegroup consisting of an alkyl group, a chlorine atom and an alkyl groupincluding a fluorine atom; R₂ is a protecting group released by an acid;and m is an integer of 0 through 5; irradiating said resist film withexposing light of a wavelength shorter than a 180 nm band for patternexposure; and forming a resist pattern by developing said resist filmafter the pattern exposure.
 18. The pattern formation method of claim17, wherein said exposing light is a Xe₂ laser beam, a F₂ laser beam, aKr₂ laser beam, an ArKr laser beam or an Ar₂ laser beam.
 19. The patternformation method of claim 17, wherein said exposing light is soft-Xrays.
 20. The pattern formation method of claim 17, wherein saidexposing light is hard-X rays.